Funding for this research was provided by:
National Natural Science Foundation of China (81872673)
National Key Research and Development Program of China (2017YFC1200203)
Received: 9 June 2019
Accepted: 17 October 2019
First Online: 28 October 2019
Ethics approval and consent to participate
: This study is a serial of phylogenetic analyses based on large scale of existing gene sequences; all these sequences can be searched and downloaded from two public databases, the NCBI Influenza Virus Sequence Database and the Global Initiative on Sharing Avian Influenza Data (GISAID) database. No institutional review board approval was required from the research ethics committee of School of Public Health, Fudan University, and animals’ ethics approval was applicable neither.
: We declare that we have no conflicts of interest.